Process for the treatment of transfer printed paper and the printed paper thus obtained

ABSTRACT

An application process is described of a polymeric carrier consisting of at least one thermoplastic polymer based on polyester or copolyester on sublimatic transfer printed paper and the transfer printed paper thus obtained. The fundamental advantage of the above process consists in the possibility of using, in the printing of vegetable fibres, existing technologies and paper currently used for the printing of polyester fabrics.

The present invention relates to a treatment process of transfer printedpaper and the transfer printed paper thus obtained.

A sublimatic printing process whereby it is possible to print polyesterfabrics with excellent results, has been known and widely used for sometime. Specific printed paper with sublimatic colours, called “transferprinted paper” is used, which when put in close contact in a hotcalender with polyester fabrics, accurately releases the colours presenton the paper onto the fabric, thus allowing the exact print present onthe paper to be repeated.

This paper is based on the sublimation principle of the dye which isabsorbed by the fibre of polyester fabric.

This printing system is currently only used for polyester fabrics, asother textile fibres, due to their incapacity to absorb dispersed orplasto-soluble dyes used in transfer printed paper, cannot be printed.

Polyamide fibres (nylon) are capable of only partially receiving dyesand can therefore only be used in a minimum percentage.

It is impossible, on the other hand, to effect the colouring ofcellulose fibres with this technique.

Sublimatic printing processes are extremely ecological printingprocesses, which are easy to apply without costly equipment andparticular design precision. For these reasons they have obtained greatcommercial success in the last few years.

It has been estimated in fact that in Europe alone, about 500 million m²of polyester fabric are printed with this system called “SublimaticTransfer Printing”.

Various studies and attempts have therefore been effected to try anddiscover how to use the sublimatic process and specific transfer printedpaper in the printing of vegetable fibres such as cotton, linen, etc.

Attempts have been made, for example, to treat cotton with specialpolymers or using various dyes in paper printing, but so far there hasbeen no success in obtaining a printing process and cotton, or vegetablefibre in general, with interesting qualitative and commercialcharacteristics.

The objective of the present invention is to identify a treatment ofpaper already printed with sublimatic colours, i.e. of transfer printedpaper, which makes it suitable for the sublimatic printing of vegetablefibres (cellulose) and mixed fibres, consequently overcoming the limitswhich characterize the known art.

An object of the present invention therefore relates to an applicationprocess of a polymeric carrier consisting of at least one thermoplasticpolymer based on polyester or copolyester to sublimatic transfer printedpaper.

A further object of the present invention relates to sublimatic transferprinted paper to which a polymeric carrier consisting of at least onethermoplastic polymer based on polyester or copolyester, has beenapplied.

The fundamental advantage of the process according to the presentinvention lies in the fact that it makes it possible to use, in theprinting of vegetable fibres, existing technologies and paper currentlyadopted for the printing of polyester fabrics.

In particular, the application process of a polymeric carrier consistingof at least one thermoplastic polymer based on polyester or copolyesterto sublimatic transfer printed paper, can be effected by melting,coupling, coating or sintering.

Application by the melting of the polymeric carrier to the sublimatictransfer printed paper can be carried out by means of bubble extrusion,in a flat head or in a calender.

Application by the coupling of the polymeric carrier to the sublimatictransfer printed paper can be carried out by the coupling of apreviously formed film.

Application by the coating of the polymeric carrier to the sublimatictransfer printed paper can be carried out by means of the rotogravure,roll revers, etc. of solutions of said polymeric carrier.

As indicated above, the dyes printed on the transfer paper belong to thechemical group of dyes called dispersed or plasto-soluble dyes.

The polymeric carrier consists of polyester and copolyesterthermoplastic polymers.

In particular, the polymeric carrier consists of polyester andcopolyester thermoplastic polymers having a melting point ranging from80 to 150° C. The melting points preferably range from 110 to 130° C.

The polyester and copolyester thermoplastic polymers are preferablyobtained by the reaction of aromatic and/or aliphatic dicarboxylic acidswith aliphatic and/or cyclic bifunctional glycols.

The aromatic and/or aliphatic dicarboxylic acids are preferably selectedfrom isophthalic acid, terephthalic acid, their anhydrides and/or theiresters, phthalic anhydride, sebacic acid, azaleic acid, adipic acid,etc.

In particular, the esters are preferably methyl esters.

The aliphatic and/or cyclic bifunctional glycols are preferably selectedfrom butanediol, ethanediol, propanediol, hexanediol, neopentylglycoland polyols such as polypropyleneglycol and polytetramethyleneglycol,etc.

In particular, polypropyleneglycol has a molecular weight ranging from500 to 1000 and polytetramethyleneglycol has a molecular weight rangingfrom 1000 to 2000.

The process according to the present invention consequently allowsprinted dyes to be transferred onto transfer printed paper, vegetableand mixed fibres under the same conditions adopted for the normalsublimatic printing of polyester fibres.

An object of the present invention also relates to the use of thetransfer printed paper obtainable with the process according to thepresent invention, for the sublimatic printing of fabrics and/orvegetable and/or mixed fibres, in particular cotton or linen fabricsand/or fibres.

The present invention also relates to a fabric or vegetable and/or mixedfibre, printed by means of a sublimatic printing process with thetransfer printed paper obtainable with the process according to thepresent invention.

The characteristics and advantages of the process and transfer printedpaper according to the present invention, can be better understood fromthe following detailed and illustrative description, referring to thefollowing examples.

EXAMPLE 1

15.5 kg of dimethylterephthalate, 15.5 kg of dimethylisophthalate, 41.4kg of 1,4-butanediol and 0.125 kg of catalyst were charged into areactor.

The mixture was then stirred and heated, by means of thermal oilexchangers, to a temperature of 245° C. for an hour and a half. Afterdistilling the methanol formed, 8.14 kg of sebacic acid were added. Thereaction was then put under vacuum at a pressure of 120 mmHg and left toreact for a further hour. The pressure was subsequently further reducedto 1 mmHg and the mixture was brought to 260° C. for two hours.

After distilling the water from the reactor, the non-reacted1,4-butanediol and possible tetrahydrofuran formed by cyclization of the1,4-butandediol, a polymer is obtained, having an intrinsic viscosityequal to 0.735 and a crystalline melting point equal to 110° C.

EXAMPLE 2

The same procedure is adopted as described in Example 1 with the onlydifference that the sebacic acid is substituted with 7.8 kg of azaleicacid.

The polymer thus obtained has an intrinsic viscosity equal to 0.715 anda crystalline melting point equal to 108° C.

The polymers obtained according to one of the above examples are thenreduced to granules and applied to the paper by means of the equipmentand processes previously indicated, thus allowing sublimatic prints tobe effected on vegetable and mixed fibres which otherwise could not beprinted with this technique.

1. An application process of a polymeric carrier consisting of at leastone thermoplastic polymer based on polyester or copolyester tosublimatic transfer printed paper.
 2. The process according to claim 1,characterized in that the application of the polymeric carrier to thetransfer printed paper is effected by means of melting, coupling,coating or sintering.
 3. The process according to claim 2, characterizedin that the application by melting is effected by means of bubbleextrusion plants, in a flat head or in a calender.
 4. The processaccording to claim 2, characterized in that the application by couplingis effected by the coupling of a previously formed polymeric film. 5.The process according to claim 2, characterized in that the applicationby coating is effected by means of a rotogravure, roll revers, etc. ofsolutions of the polymeric carrier.
 6. The process according to claim 2,characterized in that the application by sintering is effected by thesintering of powders.
 7. The process according to any of the previousclaims, characterized in that the polymeric carrier consists ofpolyester and copolyester thermoplastic polymers having melting pointsranging from 80 to 150° C.
 8. The process according to claim 7,characterized in that the melting points range from 110 to 130° C. 9.The process according to any of the previous claims, characterized inthat the polymeric carrier consists of polyester and copolyesterthermoplastic polymers obtained by the reaction of aromatic and/oraliphatic dicarboxylic acids, their anhydrides and/or their esters, withaliphatic and/or cyclic bifunctional glycols.
 10. The process accordingto claim 9, characterized in that the aromatic and/or aliphaticdicarboxylic acids and/or their anhydrides and/or their esters areselected from isophthalic acid, terephthalic acid, their anhydridesand/or their esters, phthalic anhydride, sebacic acid, azaleic acid,adipic acid.
 11. The process according to claim 10, characterized inthat the esters are methyl esters.
 12. The process according to claim 9,characterized in that the aliphatic and/or cyclic bifunctional glycolsare selected from butanediol, ethanediol, propanediol, hexanediol,neopentylglycol and polyols such as polypropyleneglycol andpolytetramethyleneglycol.
 13. The process according to claim 12,characterized in that the polypropyleneglycol has a molecular weightranging from 500 to 1000 and the polytetramethyleneglycol has amolecular weight ranging from 1000 to
 2000. 14. Sublimatic transferprinted paper to which a polymeric carrier consisting of at least onethermoplastic polymer based on polyester or copolyester, has beenapplied.
 15. Sublimatic transfer printed paper obtainable by means ofthe process according to any of the previous claims from 1 to
 13. 16.The printed paper according to claim 15, characterized in that the dyesprinted on the paper belong to the chemical group of dyes calleddispersed or plasto-soluble dyes.
 17. Use of the transfer printed paperaccording to any of the claims from 14 to 16, for the sublimaticprinting of fabrics and/or vegetable and/or mixed fibres.
 18. The useaccording to claim 17, characterized in that the fabric and/or fibre iscotton or linen.
 19. A fabric or vegetable and/or mixed fibre printed bymeans of a sublimatic printing process with the transfer printed paperaccording to one of the claims from 14 to 16.